Joint related illness or injury often limits the range of motion of a joint of an individual. In general, range of motion is the angular movement of one body portion connected to or associated with a joint to that of a second body portion also associated with the same joint. An injured elbow, for example, will have a limited range of motion in that the patient may not be able to fully extend his or her arm into a straight orientation. Physical therapy, surgery, and/or rest may be utilized in order to achieve recovery. Successful recovery of the joint is characterized by an increase in the range of motion of the joint.
Medical instruments such as goniometers are known for measuring the range of motion of flexing joints such as knees, elbows, ankles, shoulders and fingers. A typical goniometer includes a first arm and a second arm connected to one another by way of a connection that allows the two arms to pivot with respect to one another. The arms can be rotated with respect to one another a full 360°. In order to measure the range of motion of a patient's elbow a first arm of the goniometer can be aligned with the upper arm of the patient. The patient can then be asked to extend his or her arm as fully as possible. Once this is done, the healthcare provider can rotate the second arm of the goniometer so that it is aligned with the forearm of the patient. The goniometer also includes a scale that allows one to determine the angle between the first arm and the second arm. The scale can thus be utilized in order to determine the angle between the first arm and the second arm which directly correlates to the maximum range of motion of the elbow of the patient. Subsequent rest and/or physical therapy can be used to help heal the elbow and a new measurement can be taken. The range of motion of the elbow can be tracked over time to determine the effectiveness of treatment and to help ascertain the healing of the elbow.
Variations in conditions surrounding the use of goniometers exist that can result in an inaccurate measurement of the range of motion of a flexible joint. For example, the orientation on a table, chair or other object of a body part can be different between patients or can vary between the same patient when taken at different points in time. Also, the healthcare provider may align the goniometer differently with respect to a body part when conducting measurements of a patient at different points in time. Variations in measurement may be even more pronounced when aligning one of the arms of the goniometer with a body portion oriented in the vertical direction as fewer or no reference frames may be available to the healthcare provider. As such, the healthcare provider may align simply by sight an arm of the goniometer in the horizontal or vertical direction when taking measurements for ascertaining the range of motion of the patient. This practice results in inaccurate measurements when the healthcare provider misjudges the horizontal or vertical direction. As such, there remains room for variation and improvement within the art.